1. Field of the Invention
The present invention relates to a system for assembly of a rotating machine to perform data processing of measurements of each portion in an assembly work of a large rotating machine such as a gas turbine, a steam turbine and the like.
2. Description of the Prior Art
Generally, in order to assemble a large rotating machine such as a gas turbine, a steam turbine and the like, a lower half of each of an outer casing and an inner casing thereof is placed on a base stand being installed with a predetermined levelness. Then, after a rotor is installed to the lower half of the inner casing being placed, the upper half of the inner casing is assembled to the upper side of the lower half of the inner casing so as to cover the rotor, and subsequently, the upper half of the outer casing is assembled to the upper side of the lower half of the outer casing so as to cover the inner casing.
A large rotating machine being assembled as described hereinabove is so designed as to have smaller clearances between the rotor and the casing in order to enhance energy efficiency thereof. However, due to a decrease in the clearances, when each of the shaft centers of the casing serving as a stationary part and the rotor serving as a rotating part is slightly out of alignment, edges of the stationary vanes and rotating blades being installed to the casing and the rotor, respectively, come into contact with the casing and the rotor. In addition, when the casing and the rotor are axially misaligned, the casing including the stationary vanes and the rotor including the rotating blades come into contact with each other. As a result, due to the contacts as have been mentioned, there is a fear of breakage of a rotating machine when the rotating machine is rotated.
Therefore, when a large rotating machine being designed to decrease the clearances is assembled, it is necessary to measure the clearances between the casing and the rotor and adjust the positions thereof so as to make the measurement results stay within the allowable range of the designed values. When measurements are taken in order to confirm whether the clearance at each position being formed between a casing and a rotor is within the allowable range of the designed values or not, it is required that the measurements should be accurate. In order to make the clearances between the casing and the rotor appropriate, an assembly method of a steam turbine is disclosed, wherein measurement using wiring is performed to measure the positions of the stationary parts such as the casing and the like by having a piano wire being supposed as the shaft center of the rotor serve as the basis. (See the Japanese Patent Applications Laid-Open No. H6-55385 and No. H7-4207.)
In the assembly methods being disclosed in the Japanese Patent Applications Laid-Open as No. H6-55385 and No. H7-4207, after aligning the shaft center of each portion of the casing based on the measured values being obtained by the measurements using wiring, the casing and the rotor are assembled sequentially to complete assembly of a steam turbine. Moreover, in the assembly method being disclosed in the Japanese Patent Application Laid-Open as No. H6-55385, after the rotor is installed into the casing, the clearances between the inner casing and the rotor are obtained based on the results of measurements using a depth gauge, so as to make adjustments by moving the position of the inner casing.
A large rotating machine such as a steam turbine, a gas turbine and the like is assembled as described hereinabove. However, in each process of (1) when a rotor is assembled to the lower half of an inner casing, (2) when the upper half of the inner casing is assembled, (3) when the upper half of an outer casing is assembled, and (4) when all parts are assembled, deflection and distortion of the rotor and the casing occur based on the empty weight and rigidity thereof, which consequently changes the relative positions of the rotor and the casing. Therefore, it is necessary to confirm whether the clearances between the rotor and the casing are within an appropriate range or not.
In order to confirm whether or not the axial or radial clearances between the rotor and the casing are within the appropriate range, respectively, not only there are so many points to measure the clearances but also measurable points and non-measurable points are different in each work process. Therefore, conventionally, it is necessary for a worker to check each measurement part, and there is a potentiality that missing of measurement might occur. In addition, for non-measurable points, calculations for correction are done, using the measured values being obtained at the measurable points. However, because different workers do the calculations for correction for each point, activities thereof become cumbersome. Hereat, it is necessary to determine parameters for the calculations for correction, based on the empty weight and rigidity of the casing and the rotor of a large rotating machine to be assembled, which further makes activities of the calculations for correction cumbersome and complicated.